The Window Menu

The window menu (also known as the System menu or Control menu) is a pop-up menu defined and managed almost exclusively by the operating system. The user can open the window menu by clicking the application icon on the title bar or by right-clicking anywhere on the title bar.

The window menu provides a standard set of menu items that the user can choose to change a window's size or position, or close the application. Items on the window menu can be added, deleted, and modified, but most applications just use the standard set of menu items. An overlapped, pop-up, or child window can have a window menu. It is uncommon for an overlapped or pop-up window not to include a window menu.

When the user chooses a command from the window menu, Windows sends a WM_SYSCOMMAND message to the menu's owner window. In most applications, the window procedure does not process messages from the window menu. Instead, it simply passes the messages to the DefWindowProc function for system-default processing of the message. If an application adds a command to the window menu, the window procedure must process the command.

An application can use the GetSystemMenu function to create a copy of the default window menu to modify. Any window that does not use the GetSystemMenu function to make its own copy of the window menu receives the standard window menu.